The {\textquotedblleft}Reconnecting Floodplains and Restoring Green Space as a Management Strategy to Minimize Risk and Increase Resilience in the Context of Climate and Landscape Change{\textquotedblright} project consists of two studies, both of which result in deliverable findings. The first builds a hydraulic model that successfully projects how land use and flooding frequency in the Maidstone Bends floodplain impact the Connecticut River. The second develops a spatial model that successfully maps sandbars within a watershed and provides\ information about how the sediment moves and deposits in a river. Both of these models are potential tools for floodplain connectivity projects that seek to manage floodplain habitats for the benefit of human communities and ecological integrity.\

The findings suggest that floodplain restoration can strengthen flood management, but full restoration is unnecessary to enhance protection against floods. Smaller restoration projects can reduce flood peaks while lessening the negative social and economic impacts on people and property located downstream. In the river itself, the largest sandbars are found in unregulated rivers where naturally eroding banks contribute more sediment. In all 13 rivers, sandbars decrease downstream, due to natural sedimentation patterns and storage of sediment in dams. Dam management changes may alleviate the impacts of diminished sediment loads.

Production of biomass is central to the ecology and sustainability of fish assemblages. The goal of this study was to empirically estimate and compare fish assemblage production, production-to-biomass (P/B) ratios and species composition for 25\ second- to third-order streams spanning the Appalachian Mountains (from Vermont to North Carolina) that vary in their temperature regimes. Fish assemblage production estimates ranged from 0.15 to 6.79\ g\ m-2\ year-1, and P/B ratios ranged from 0.20 to 1.07. There were no significant differences in mean assemblage production across northern cold-water, southern cold-water and southern cool-water streams (p\ =\ .35). Two warm-water streams, not included in these comparisons, had the highest mean production and biomass values. Mean assemblage P/B was significantly higher in northern cold-water streams relative to southern cold-water and cool-water streams (p\ =\ .01). Species evenness in production declined with stream temperature and differed significantly across the lower latitude cold-water, cool-water and warm-water streams and the higher latitude (i.e. more northern) cold-water streams. Our fish assemblage production estimates and P/B ratios were both lower and higher compared to previously published estimates for similar stream habitats. This study provides empirical fish assemblage production estimates to inform future research on southern Appalachian streams and on the potential impacts of varying temperature regimes on cold-water, cool-water and warm-water fish production in the coming decades as climate change continues to threaten fish assemblages.

Genetic rescue is an increasingly considered conservation measure to address genetic erosion associated with habitat loss and fragmentation. The resulting gene flow from facilitating migration may improve fitness and adaptive potential, but is not without risks (e.g., outbreeding depression). Here, we conducted a test of genetic rescue by translocating ten (five of each sex) brook trout (Salvelinus fontinalis) from a single source to four nearby and isolated stream populations. To control for the demographic contribution of translocated individuals, ten resident individuals (five of each sex) were removed from each recipient population. Prior to the introduction of translocated individuals, the two smallest above-barrier populations had substantially lower genetic diversity, and all populations had reduced effective number of breeders relative to adjacent below-barrier populations. In the first reproductive bout following translocation, 31 of 40 (78\%) translocated individuals reproduced successfully. Translocated individuals contributed to more families than expected under random mating and generally produced larger full-sibling families. We observed relatively high (\>20\%) introgression in three of the four recipient populations. The translocations increased genetic diversity of recipient populations by 45\% in allelic richness and 25\% in expected heterozygosity. Additionally, strong evidence of hybrid vigour was observed through significantly larger body sizes of hybrid offspring relative to resident offspring in all recipient populations. Continued monitoring of these populations will test for negative fitness effects beyond the first generation. However, these results provide much-needed experimental data to inform the potential effectiveness of genetic rescue-motivated translocations.

Understanding how multiple extrinsic (density-independent) factors and intrinsic (density-dependent) mechanisms influence population dynamics has become increasingly urgent in the face of rapidly changing climates. It is particularly unclear how multiple extrinsic factors with contrasting effects among seasons are related to declines in population numbers and changes in mean body size and whether there is a strong role for density-dependence. The primary goal of this study was to identify the roles of seasonal variation in climate driven environmental direct effects (mean stream flow and temperature) vs. density-dependence on population size and mean body size in eastern brook trout (Salvelinus fontinalis). We use data from a 10-year capture-mark-recapture study of eastern brook trout in four streams in Western Massachusetts, USA to parameterize a discrete-time population projection model. The model integrates matrix modeling techniques used to characterize discrete population structures (age, habitat type, and season) with integral projection models (IPMs) that characterize demographic rates as continuous functions of organismal traits (in this case body size). Using both stochastic and deterministic analyses we show that decreases in population size are due to changes in stream flow and temperature and that these changes are larger than what can be compensated for through density-dependent responses. We also show that the declines are due mostly to increasing mean stream temperatures decreasing the survival of the youngest age class. In contrast, increases in mean body size over the same period are the result of indirect changes in density with a lesser direct role of climate-driven environmental change.

Water temperature is a primary driver of stream ecosystems and commonly forms the basis of stream classifications. Robust models of stream temperature are critical as the climate changes, but estimating daily stream temperature poses several important challenges. We developed a statistical model that accounts for many challenges that can make stream temperature estimation difficult. Our model identifies the yearly period when air and water temperature are synchronized, accommodates hysteresis, incorporates time lags, deals with missing data and autocorrelation and can include external drivers. In a small stream network, the model performed well (RMSE = 0.59{\textdegree}C), identified a clear warming trend (0.63 {\textdegree}C decade-1) and a widening of the synchronized period (29 d decade-1). We also carefully evaluated how missing data influenced predictions. Missing data within a year had a small effect on performance (\~{}0.05\% average drop in RMSE with 10\% fewer days with data). Missing all data for a year decreased performance (\~{}0.6 {\textdegree}C jump in RMSE), but this decrease was moderated when data were available from other streams in the network.

Dam removal is becoming an increasingly important component of river restoration, with \>\ 1100 dams having been removed nationwide over the past three decades. Despite this recent progression of removals, the lack of pre- to post-removal monitoring and assessment limits our understanding of the magnitude, rate, and sequence of geomorphic and/or ecological recovery to dam removal. Taking advantage of the November 2012 removal of an old (~\ 190\ year-old) 6-m high, run-of-river industrial dam on Amethyst Brook (26\ km2) in central Massachusetts, we identify the immediate eco-geomorphic responses to removal. To capture the geomorphic responses to dam removal, we collected baseline data at multiple scales, both upstream (~\ 300\ m) and downstream (\>\ 750\ m) of the dam, including monumented cross sections, detailed channel-bed longitudinal profiles, embeddedness surveys, and channel-bed grain size measurements, which were repeated during the summer of 2013. These geomorphic assessments were combined with detailed quantitative electrofishing surveys of stream fish richness and abundance above and below the dam site and throughout the watershed and visual surveys of native anadromous sea lamprey (Petromyzon marinus) nest sites. Post-removal assessments were complicated by two events: (1) upstream knickpoint migration exhumed an older (ca. late eighteenth century) intact wooden crib dam ~\ 120\ m upstream of the former stone dam, and (2) the occurrence of a 10{\textendash}20\ year RI flood 6\ months after removal that caused further upstream incision and downstream aggradation. Now that the downstream reach has been reconnected to upstream sediment supply, the predominant geomorphic response was bed aggradation and associated fining (30{\textendash}60\% reduction). At dam proximal locations, aggradation ranged from 0.3 to \>\ 1\ m where a large woody debris jam enhanced aggradation. Although less pronounced, distal locations still showed aggradation with a mean depth of deposition of ~\ 0.20\ m over the 750-m downstream reach. Post-removal, but pre-flood, bed surveys indicate ~\ 2\ m of incision had migrated 25\ m upstream of the former reservoir before encountering the exhumed dam, which now acts as the new grade control, limiting progressive headcutting. Approximately 1000\ m3\ of sediment was evacuated in the first year, with ~\ 67\% of the volume occurring by pre-flood, process-driven (e.g., changes in base level) controls. The combination of changes in channel-bed sedimentology, the occurrence of a large magnitude flood, and the emergence of the new crib dam that is a likely barrier to fish movement was associated with major reductions in abundance and richness in sites downstream and immediately upstream adjacent to the former dam in post-removal sampling. At the same time, we documented the presence of four species of fish, including sea lamprey, which were not present above the dam prior to removal, indicating that upstream passage has been achieved; and we also documented lamprey spawning activity at sites immediately below the dam, which had previously been unsuitable owing to an excessively coarse and armored riverbed. Our results point to the importance of interactions between dam removal and flood disturbance effects, with important implications for short- and long-term monitoring and assessment of dam impacts to river systems.

Landscape form represents the cumulative effects of de-stabilizing events relative to recovery processes. Most geomorphic research has focused on the role of episodic rare events on landscape form with less attention paid to the role and persistence of chronic inputs. To better establish the interplay between chronic and episodic extreme events at regional scales, we used aerial photography and post-flood sediment sampling to assess stream and hillslope response and recovery to a 100{\textendash}300 yr. flood caused by Tropical Storm Irene in New England. Within a 14 000 km2\ study area, analysis of aerial photographs indicated that the storm initiated (n = 534) and reactivated (n = 460) a large number of landslides. These landslides dramatically increased overall estimates of regional erosion rates (from 0.0023 mm/yr. without Irene to 0.0072 mm/yr. with Irene). Similarly, Irene-generated LWD inputs of 0.25{\textendash}0.5 trees/km exceeded annual background rates in a single event, and these concentrated inputs (101{\textendash}102\ of trees/landslide) are likely to result in large jams and snags that are particularly persistent and geomorphically effective. Finally, we found that landslide scars continue to provide elevated sediment inputs years after the event, as evidenced by sustained higher suspended sediment concentrations in streams with Irene-generated landslides. Overall, our results indicate that infrequent, high-magnitude events have a more important geomorphic role in tectonically stable, more moderate-relief systems than has been previously recognized. Understanding the role of these events has particular relevance in regions such as New England, where the frequency and magnitude of extreme storms is expected to increase. Further, these effects may force reconsideration of conservation and restoration targets (for example in channel form and large wood loading and distribution) in fluvial systems. Copyright {\textcopyright} 2016 John Wiley \& Sons, Ltd.

We analyzed the associations of catchment-scale and riparian-scale environmental factors with occurrence of Brook Trout Salvelinus fontinalis in Connecticut headwater stream segments with catchment areas of \<15 km2. A hierarchical Bayesian approach was applied to a statewide stream survey data set, in which Brook Trout detection probability was incorporated and statistical significance of environmental covariates was based on 95\% credible intervals of estimated coefficients that did not overlap a value of zero. Forested land at the catchment scale was the most important covariate affecting Brook Trout occurrence; i.e., heavily forested catchments with corresponding low levels of developed and impervious land area were more likely to be occupied by Brook Trout. Coarse surficial geology (an indicator of groundwater potential) and stream slope had significantly positive effects on occurrence, whereas herbaceous plant cover and wetland and open water area had significantly negative effects. Catchment-scale and riparian-scale covariates were highly correlated in many instances, and no riparian-scale covariate was retained in the final model. Detection probability of Brook Trout at the stream-segment scale was high (mean, 0.85). Our model had a high predictive ability, and the mean value of receiver operating characteristic area under the curve was 0.80 across 100 leave-some-out iterations. The fine spatial grain of this study identified patches of suitable stream habitat for Brook Trout in Connecticut, particularly in the northwestern part. Our analysis revealed a more optimistic status of Brook Trout in Connecticut than did a coarser-grained analysis across the USA.

As a growing body of science shows, climate change impacts on wildlife are already profound {\textemdash} from shifting species{\textquoteright} ranges and altering the synchronicity of food sources to changing the availability of water. Such impacts are only expected to increase in the coming decades. As climate change shapes complex, interwoven ecological processes, novel conditions and ecosystems will continue to emerge. This reality poses unprecedented challenges, but also opportunities for natural resource managers as they plan for the decades to come.

Headwater stream ecosystems are vulnerable to numerous threats associated with climate and land use change. In the northeastern US, many headwater stream species (e.g., brook trout and stream salamanders) are of special conservation concern and may be vulnerable to climate change influences, such as changes in stream temperature and streamflow. Federal land management agencies (e.g., US Fish and Wildlife Service, National Park Service, USDA Forest Service, Bureau of Land Management and Department of Defense) are required to adopt policies that respond to climate change and may have longer-term institutional support to enforce such policies compared to state, local, non-governmental, or private land managers. However, federal agencies largely make management decisions in regards to headwater stream ecosystems independently. This fragmentation of management resources and responsibilities across the landscape may significantly impede the efficiency and effectiveness of conservation actions, and higher degrees of collaboration may be required to achieve conservation goals. This project seeks to provide an example of cooperative landscape decision-making to address the conservation of headwater stream ecosystems. We identified shared and contrasting objectives of each federal agency and potential collaboration opportunities that may increase efficient and effective management of headwater stream ecosystems in two northeastern US watersheds. These workshops provided useful insights into the adaptive capacity of federal institutions to address threats to headwater stream ecosystems. Our ultimate goal is to provide a decision-making framework and analysis that addresses large-scale conservation threats across multiple stakeholders, as a demonstration of cooperative landscape conservation for aquatic ecosystems. Additionally, we aim to provide new scientific knowledge and a regional perspective to resource managers to help inform local management decisions.

},
keywords = {brook trout, climate change, federal agencies, headwater streams, Salamanders, structured decision making},
author = {Katz, Rachel and Evan H. Campbel Grant and Runge, Michael C. and Connery, Bruce and Crockett, Marquette and Herland, Libby and Johnson, Sheila and Kirk, Dawn and Wofford, Jeb and Bennett, Rick and Nislow, Keith H. and Norris, Marian and Hocking, Daniel J. and Letcher, Benjamin H. and Roy, Allison}
}
@article {1092,
title = {Ranking Site Vulnerability to Increasing Temperatures in Southern Appalachian Brook Trout Streams in Virginia: An Exposure-Sensitivity Approach},
journal = {Transactions of the American Fisheries Society},
volume = {143},
year = {2014},
month = {01/2014},
pages = {173 - 187},
abstract = {Models based on simple air temperature{\textendash}water temperature relationships have been useful in highlighting potential threats to coldwater-dependent species such as Brook Trout Salvelinus fontinalis by predicting major losses of habitat and substantial reductions in geographic distribution. However, spatial variability in the relationship between changes in air temperature to changes in water temperature complicates predictions. We directly measured paired summer air and water temperatures over 2 years in a stratified representative sample of watersheds (<1{\textendash}274 km2) supporting wild Brook Trout throughout Virginia near the southern edge of the species distribution. We used the temperature data to rank streams in terms of two important components of habitat vulnerability: sensitivity (predicted change in water temperature per unit increase in air temperature) and exposure (predicted frequency, magnitude, and duration of threshold water temperatures). Across all sites, sensitivity was substantially lower (median sensitivity = 0.35{\textdegree}C) than the 0.80{\textdegree}C assumed in some previous models. Median sensitivity across all sites did not differ between the 2 years of the study. In contrast, median exposure was considerably greater in 2010 (a particularly warm summer) than in 2009, but exposure ranks of habitat patches were highly consistent. Variation in sensitivity and exposure among habitat patches was influenced by landscape metrics (percent forested riparian corridor, patch area, and elevation), but considerable unexplained variation in sensitivity and exposure among sites was likely due to local-scale differences in the extent of groundwater influence. Overall, our direct measurement approach identified significantly more Brook Trout habitat patches with low sensitivity and low exposure that may persist under warming air temperatures than did previous large-scale models. Our sensitivity and exposure classification should provide a useful general framework for managers in making investment decisions for protecting and restoring Brook Trout habitat.},
keywords = {brook trout, cold water species, sensitivity analysis},
issn = {1548-8659},
doi = {10.1080/00028487.2013.835282},
author = {Trumbo, Bradly A. and Nislow, Keith H. and Stallings, Jonathan and Hudy, Mark and Smith, Eric P. and Kim, Dong-Yun and Wiggins, Bruce and Dolloff, Charles A.}
}
@article {1625,
title = {Riparian Prioritization and Status Assessment for Climate Change Resilience of Coldwater Stream Habitats within the Appalachian and Northeastern Regions},
year = {2014},
month = {08/2014},
institution = {University of Massachusetts Department of Environmental Conservation and US Forest Service Northern Research Station},
abstract = {

Among a host of other critical ecosystem functions, intact riparian forests can help to reduce vulnerability of coldwater stream habitats to warming regional temperatures. Restoring and conserving these forests can therefore be an important part of regional and landscape-scale conservation plans, but managers need science and decision-support tools to help determine when these actions will be most effective. To help fill this need, we developed the Riparian Prioritization for Climate Change Resilience (RPCCR) web-based decision support tool to quickly and easily identify, based on current riparian cover and predicted vulnerability to air temperature warming, sites that are priority candidates for riparian restoration and conservation. This tool was successfully incorporated into the suite of open-source data layers and delineation tools currently served by the Appalachian Landscape Conservation Cooperative, including the Eastern Brook Trout Assessment. Critical objectives included 1) transfer of the RPCCR to an Open-Source platform (from ARC-GIS) 2) extension of the RPCCR range-wide 3) ability to prioritize sites at any user-determined spatial scale 4) input from, and training for, users and stakeholders. In addition to development and application of the RPCCR, we used the riparian and landscape-level spatial coverages to establish current riparian cover levels across the entire range with the goal of comparing cover levels across jurisdictions and catchments with and ithout brook trout and other salmonids, and to serve as a baseline for future detection of status and trends.

},
keywords = {decision support, riparian forests},
url = {http://applcc.org/research/dst-restoration-under-climate-change-group/riparian-prioritization-and-status-assessment-for-climate-change-resilience-of-coldwater-stream-habitats-within-the-appalachian-and-northeastern-regions},
author = {Coombs, Jason A. and Nislow, Keith H.}
}
@article {1472,
title = {Robust estimates of environmental effects on population vital rates: an integrated capture-recapture model of seasonal brook trout growth, survival and movement in a stream network},
journal = {Journal of Animal Ecology},
year = {2014},
month = {11/2014},
pages = {n/a - n/a},
abstract = {1. Modelling the effects of environmental change on populations is a key challenge for ecologists, particularly as the pace of change increases. Currently, modelling efforts are limited by difficulties in establishing robust relationships between environmental drivers and population responses. 2. We developed an integrated capture{\textendash}recapture state-space model to estimate the effects of two key environmental drivers (stream flow and temperature) on demographic rates (body growth, movement and survival) using a long-term (11 years), high-resolution (individually tagged, sampled seasonally) data set of brook trout (Salvelinus fontinalis) from four sites in a stream network. Our integrated model provides an effective context within which to estimate environmental driver effects because it takes full advantage of data by estimating (latent) state values for missing observations, because it propagates uncertainty among model components and because it accounts for the major demographic rates and interactions that contribute to annual survival. 3. We found that stream flow and temperature had strong effects on brook trout demography. Some effects, such as reduction in survival associated with low stream flow and high temperature during the summer season, were consistent across sites and age classes, suggesting that they may serve as robust indicators of vulnerability to environmental change. Other survival effects varied across ages, sites and seasons, indicating that flow and temperature may not be the primary drivers of survival in those cases. Flow and temperature also affected body growth rates; these responses were consistent across sites but differed dramatically between age classes and seasons. Finally, we found that tributary and mainstem sites responded differently to variation in flow and temperature. 4. Annual survival (combination of survival and body growth across seasons) was insensitive to body growth and was most sensitive to flow (positive) and temperature (negative) in the summer and fall. 5. These observations, combined with our ability to estimate the occurrence, magnitude and direction of fish movement between these habitat types, indicated that heterogeneity in response may provide a mechanism providing potential resilience to environmental change. Given that the challenges we faced in our study are likely to be common to many intensive data sets, the integrated modelling approach could be generally applicable and useful.},
keywords = {annual survival, Bayesian modelling, capture{\textendash}mark{\textendash}recapture, integrated model, movement, SENSITIVITY, stream fish, stream network, Survival},
doi = {10.1111/1365-2656.12308},
author = {Letcher, Benjamin H. and Schueller, Paul and Bassar, Ronald D. and Nislow, Keith H. and Coombs, Jason A. and Sakrejda, Krzysztof and Morrissey, Michael and Sigourney, Douglas B. and Whiteley, Andrew R. and O{\textquoteright}Donnell, Matthew J. and Dubreuil, Todd L.}
}
@article {58,
title = {Context-specific influence of water temperature on brook trout growth rates in the field},
journal = {Freshwater Biology},
year = {2010},
month = {04/2010},
pages = {no - no},
abstract = {1. Modelling the effects of climate change on freshwater fishes requires robust field-based estimates accounting for interactions among multiple factors. 2. We used data from an 8-year individual-based study of a wild brook trout (Salvelinus fontinalis) population to test the influence of water temperature on season-specific growth in the context of variation in other environmental (i.e. season, stream flow) or biotic factors (local brook trout biomass density and fish age and size) in West Brook, a third-order stream in western Massachusetts, U.S.A. 3. Changes in ambient temperature influenced individual growth rates. In general, higher temperatures were associated with higher growth rates in winter and spring and lower growth rates in summer and autumn. However, the effect of temperature on growth was strongly context-dependent, differing in both magnitude and direction as a function of season, stream flow and fish biomass density. 4. We found that stream flow and temperature had strong and complex interactive effects on trout growth. At the coldest temperatures (in winter), high stream flows were associated with reduced trout growth rates. During spring and autumn and in typical summers (when water temperatures were close to growth optima), higher flows were associated with increased growth rates. In addition, the effect of flow at a given temperature (the flow-temperature interaction) differed among seasons. 5. Trout density negatively affected growth rate and had strong interactions with temperature in two of four seasons (i.e. spring and summer) with greater negative effects at high temperatures. 6. Our study provided robust, integrative field-based estimates of the effects of temperature on growth rates for a species which serves as a model organism for cold-water adapted ectotherms facing the consequences of environmental change. Results of the study strongly suggest that failure to derive season-specific estimates, or to explicitly consider interactions with flow regime and fish density, will seriously compromise our ability to predict the effects of climate change on stream fish growth rates. Further, the concordance we found between empirical observations and likely energetic mechanisms suggests that our general results should be relevant at broader spatial and temporal scales.},
keywords = {brook trout, climate science center, density dependence, New England Climate, season-specific growth, stream flow, water temperature},
author = {XU, CAILIN and Letcher, Benjamin H. and Nislow, Keith H.}
}
@article {56,
title = {Size-dependent survival of brook trout Salvelinus fontinalis in summer: effects of water temperature and stream flow},
journal = {Journal of Fish Biology},
volume = {76},
year = {2010},
month = {06/2010},
pages = {2342 - 2369},
abstract = {A 5 year individual-based data set was used to estimate size-specific survival rates in a wild brook trout Salvelinus fontinalis population in a stream network encompassing a mainstem and three tributaries (1{\textbullet}5{\textendash}6 m wetted width), western Massachusetts, U.S.A. The relationships between survival in summer and temperature and flow metrics derived from continuous monitoring data were then tested. Increased summer temperatures significantly reduced summer survival rates for S. fontinalis in almost all size classes in all four sites throughout the network. In contrast, extreme low summer flows reduced survival of large fish, but only in small tributaries, and had no significant effects on fish in smaller size classes in any location. These results provide direct evidence of a link between season-specific survival and environmental factors likely to be affected by climate change and have important consequences for the management of both habitats and populations.},
keywords = {climate change, climate science center, New England Climate, salmonids, size-dependent survival, stream discharge},
author = {XU, CAILIN and Letcher, Benjamin H. and Nislow, Keith H.}
}
@article {111,
title = {Population Response to Habitat Fragmentation in a Stream-Dwelling Brook Trout Population},
journal = {PLoS ONE},
volume = {2},
year = {2007},
month = {11/2007},
pages = {e1139},
abstract = {Fragmentation can strongly influence population persistence and expression of life-history strategies in spatially-structured populations. In this study, we directly estimated size-specific dispersal, growth, and survival of stream-dwelling brook trout in a stream network with connected and naturally-isolated tributaries. We used multiple-generation, individual-based data to develop and parameterize a size-class and location-based population projection model, allowing us to test effects of fragmentation on population dynamics at local (i.e., subpopulation) and system-wide (i.e., metapopulation) scales, and to identify demographic rates which influence the persistence of isolated and fragmented populations. In the naturally-isolated tributary, persistence was associated with higher early juvenile survival (\~{}45\% greater), shorter generation time (one-half) and strong selection against large body size compared to the open system, resulting in a stage-distribution skewed towards younger, smaller fish. Simulating barriers to upstream migration into two currently-connected tributary populations caused rapid (2{\textendash}6 generations) local extinction. These local extinctions in turn increased the likelihood of system-wide extinction, as tributaries could no longer function as population sources. Extinction could be prevented in the open system if sufficient immigrants from downstream areas were available, but the influx of individuals necessary to counteract fragmentation effects was high (7{\textendash}46\% of the total population annually). In the absence of sufficient immigration, a demographic change (higher early survival characteristic of the isolated tributary) was also sufficient to rescue the population from fragmentation, suggesting that the observed differences in size distributions between the naturally-isolated and open system may reflect an evolutionary response to isolation. Combined with strong genetic divergence between the isolated tributary and open system, these results suggest that local adaptation can {\textquoteleft}rescue{\textquoteright} isolated populations, particularly in one-dimensional stream networks where both natural and anthropogenically-mediated isolation is common. However, whether rescue will occur before extinction depends critically on the race between adaptation and reduced survival in response to fragmentation.},
keywords = {climate science center},
author = {Letcher, Benjamin H. and Nislow, Keith H. and Coombs, Jason A. and O{\textquoteright}Donnell, Matthew J. and Dubreuil, Todd L.}
}
@article {129,
title = {Mechanistic Linkage of Hydrologic Regime to Summer Growth of Age-0 Atlantic Salmon},
journal = {Transactions of the American Fisheries Society},
volume = {133},
year = {2004},
month = {1/2004},
pages = {79 - 88},
abstract = {Significant reductions in juvenile stream salmonid growth have been observed in association with low summer flow, but underlying mechanisms are poorly understood and predictive power is limited. We conducted a stage-specific analysis of the relationship between summer flow and the growth of age-0 Atlantic salmon Salmo salar in two rearing sites in the upper Connecticut River basin, New Hampshire. We contrasted effects of variation in foraging habitat availability and temperature on individual age-0 Atlantic salmon mass during one high-flow year and two low-flow years and from high- and low-flow sites within years. Overall age-0 Atlantic salmon mass was positively correlated with the availability of model-predicted favorable foraging locations and negatively correlated with density during the summer. Individual Atlantic salmon mass and the proportion of temperature-predicted maximum mass were lowest during the two low-flow years and were lower in upstream than in downstream sections. Between-year variation in growth was not closely associated with temperature model predictions. However, some of the difference between upstream and downstream sections appeared to be associated with lower summer temperatures in the upstream section. Our case study provides a framework for combining empirical and modeling approaches to quantify the potential impact of hydrologic change on fish growth and for linking variation in stream discharge to juvenile Atlantic salmon performance across time and space.},
keywords = {climate science center, New England Climate},
author = {Nislow, Keith H. and Sepulveda, A. J. and Folt, C. L.}
}
@article {128,
title = {Phosphorus flux due to Atlantic salmon (Salmo salar) in an oligotrophic upland stream: effects of management and demography},
journal = {Canadian Journal of Fisheries and Aquatic Sciences},
volume = {61},
year = {2004},
month = {2004},
pages = {2401 - 2410},
abstract = {Little is known concerning the role of Atlantic salmon (Salmo salar) in the transport of nutrients to and from river systems. We used demographic data from the River Bran, an oligotrophic river in Scotland, UK, to construct a budget for the transport of phosphorus (P) and applied it to investigate the effects of management strategies and demographic rates on potential transport. At present, because few adults return to their spawning grounds, salmon export 0.2{\textendash}0.5 kg P{\textbullet}year{\textendash}1. In contrast, increasing passage rates to a level sufficient to maintain a population without stocking would likely result in a gain of up to several kilograms per year. However, this effect depended on the retention of adult-derived P, which varies across systems and is poorly known at present. Egg-derived P exceeded that from adults at low (<25\%) retention rates but was insufficient on its own to balance losses. Increased marine survival rates also increased the potential for positive P flux, while reduction in egg{\textendash}smolt survival reduced the magnitude of transport. These results indicate the importance of considering within-river movements of individuals and nutrients and the need to fill critical data gaps in assessing the role of Atlantic salmon in nutrient transport.},
keywords = {climate science center},
author = {Nislow, Keith H. and Armstrong, John D. and McKelvey, Simon}
}